Electric aspirations and diesel engine technology are coming together at one of Sweden’s biggest engineering companies
Few engine makers have the chance to test new ideas on a whole city. But the town of Gothenburg in Sweden is becoming a testbed for its best-known exporter, automotive group Volvo, as it and marine engine division Volvo Penta develop new concepts in electric propulsion and transport connectivity.
The project started in 2004 with the introduction of the first Volvo hybrid electric bus. The first fully electric bus followed on route 55 four years ago. The vehicles have since been introduced on routes across the city, each using a single electric motor powered by roof-mounted batteries. Now the network of ferries operated by Styrsöbolaget crossing the Göta Älv river are in line for electrification. Next year Volvo Penta plans to begin by converting Älvsnabben 4, one of the small double-ended ferries that zigzag through the city.
To prepare for the move, the company has begun work on a prototype fully electric vessel at its testing base Krossholmen. When Volvo Penta director of new technology Thorbjörn Lundqvist showed Marine Propulsion around the prototype in late May, the installation was complete but not yet powered up. Four 50kWh battery packs were connected via reduction gears and electric drives to two manoeuvrable Volvo Penta IPS thrusters, with heat exchangers to cool power electronics and DC-DC converters enabling the batteries to take charge.
The test boat took under four months to build and tests in the water are due to begin, according to Volvo Penta director of electromobility Niklas Thulin.
“We are learning valuable lessons about designing battery rooms and new opportunities with weight distribution, which will give us the ability to optimise the balance and ride quality of vessels,” he said. “The electric driveline will have different dynamics compared to a combustion engine. Our objective is to fine tune these to improve the experience, but not make it so different that the vessel’s crew need to be retrained.”
Johan Inden (Volvo Penta): “We want to become the world leader in sustainable transport across all sectors"
The ferry will initially run a generator on renewable fuel to provide electricity. In a second stage, the partners will examine options for charging the batteries through a shore connection. The companies aim to put the ferry in to service at the end of 2020.
Like the first electric bus in Gothenburg, the prototype of the ferry deploys a Volvo, rather than Volvo Penta, electric drivetrain (with the exception of the IPS propulsion). This will be a valuable assistance to the marine business as it learns from a proven system and integrates it with its own electric vessel controls.
“After this we will know how to manage the electromobility driveline and optimise it for marine,” says Mr Lundqvist. “We want to be able to give our customers specific marine features, easy installation and support that works.”
The focus on electric vessels should not come as a surprise to those who understand the Swedish company’s wider strategy, says Volvo Penta president Europe region Johan Inden. “We want to become the world leader in sustainable transport across all sectors. That frames all our investments.”
But that ambition does not mean that the company is happy to forget its existing portfolio or its engine focus. Mr Inden believes in the transition to electric vessels, but sees that happening over a period of decades. Meanwhile, investment is continuing in its diesel engine range and in June the company unveiled several upgrades to its engines. At the top end of the power range, Volvo Penta has increased the power output for its D16 engines – often used as an auxiliary engine in the shortsea shipping sector – to meet the growing demand for electricity generation in that market.
“After this we will know how to manage the electromobility driveline and optimise it for marine”
“An electrical output of 450 or 500kWe has developed into a near standard for coastal heavy-duty installations where gensets are part of the propulsion system,” explains Volvo Penta product planning manager, marine commercial Thomas Lantz.
The IMO Tier II-compliant engines now produce 479kW at 1,500 rpm and 532kW at 1,800 rpm, corresponding to 450kWe through a 50Hz genset and 500kWe through a 60Hz genset. The upgraded engine, Volvo Penta’s most powerful, has also achieved a 3% fuel consumption improvement compared with the previous version.
Hybridisation and compliance
The enginebuilder has also been making strides to widen the commercial applications for its smaller engines. The six-cylinder, 7.7-l D8 engine was first introduced in 2016 for high speed and leisure applications. That launch was followed by a new variant that boasted a 3-4 rating, making it suitable for commercial light duty vessels. Volvo Penta has now introduced a 1-2 rated engine for heavy-duty applications, including tugboats and other work vessels.
The rebuilt D8 heavy-duty engine features common-rail fuel injection, double overhead camshafts and twin-entry turbocharger. A genset based on the new heavy duty D8 will deliver electrical power ranging from 136kWe to 250kWe. The current version complies with IMO Tier II NOx limits as well as EPA 3 and China 2 ratings.
A Tier III- and EU Inland Waterway stage V-compliant engine is planned for release in mid-2020, using selective catalytic reduction (SCR) to meet sulphur requirements.
“We’ve opted for the use of SCR because it keeps the engine working efficiently with optimised fuel consumption and keeps the power up to the right level,” says Mr Lantz.
Volvo Penta initially launched its IMO III solution for its 13-litre engines before making it available for other marine propulsion and genset applications.
“The IMO Tier III solution for the D13 has proven itself in tough marine conditions, having undergone 35,000 hours of field-testing prior to its launch in 2018,” explains Mr Lantz. “The new D8 IMO III engine has been developed to sustain high back pressure while also maintaining efficiency and drivability.”
The new extensions to Volvo Penta’s range include engines developed with hybridisation in mind, with two gensets among the offering. These can be seen as the connection between Volvo Penta’s current portfolio and its focus on electric drivetrains. For the next several years, fully electric vessels will have limited applications on short, fixed routes between charges. Any electrification of vessels with a varied operation will require hybrid technology.
Volvo Penta is exploring hybrid technologies – again using Gothenburg as a testbed. And there are other technologies far beyond propulsion on trial. When Marine Propulsion visited, the company was testing a camera fusion technology to give crew a bird’s eye view of a vessel as it docked, for example. That ambition is all part of preparing for an electric and automated future in which Volvo Penta sees itself playing a role far wider than designing engines.